salty Posted June 18, 2016 Report Posted June 18, 2016 I'm curious if any of you have this style ram hose. I found out that mine is not hooked up to anything and nobody I've talked to can figure out what exactly is set up wrong. I can't find anything in service manuals or parts manuals that helps. If you've got this style, can you snap a pic or two of where it's going?
salty Posted June 18, 2016 Author Report Posted June 18, 2016 Stupid phone, this was supposed to be posted in pre-j moony forum....
Johnnybgoode Posted June 18, 2016 Report Posted June 18, 2016 Same story here I remember going over this with a mechanic a couple years ago - two possibilities are emerging from the fog. One, back to the fuel pump. The other, to the generator. I honestly don't recall what we settled on but can check tomorrow if no one provides a better answer. Patrick
carusoam Posted June 20, 2016 Report Posted June 20, 2016 65C gets a generator shroud. If you have an alternator, the generator and it's shroud is missing too... Best regards, -a- 1
salty Posted June 20, 2016 Author Report Posted June 20, 2016 We considered the generator, there is a port on the back, but it's only 3/4" where the ram hole is 1 1/4" and it would be trying to flow air back into the front of the generator which is under high pressure, so that didn't make sense. Our other theory is that it could be providing an unfiltered alternate air source sans carb heat, since there is a valve on a 1 1/4" intake but there's nothing in the cabin to actuate that valve independently. Right now the valve actuated when carb heat is engaged.
DXB Posted June 20, 2016 Report Posted June 20, 2016 I'd like to know the answer to this one too. I have the same hole with mesh cover on my 68C, but there is nothing attached behind it - just opens into the bottom cowl. I have an alternator, so it would make sense if it served the generator and was thus removed. It might raise air pressure in the bottom cowl and thus decrease airflow over the tops of the cylinders - should I just seal it from behind?
Andy95W Posted June 20, 2016 Report Posted June 20, 2016 On my 64C (as well as my previous 67C) the SCAT tube extends aft to blow air on the mechanical fuel pump. It gets secured wherever you can to generally direct air to the back of the engine. Attached is a picture of mine. The tube in question is the one that appears to be laying on the oil cooler and runs back to where it disappears behind the #4 intake riser. As I said, it points to the mechanical fuel pump. P.S. Please feel free to comment on anything else you see in the photo that is wrong (especially M20Doc- Clarence). I took this picture when I was doing the first annual on my (new to me) M20C. It doesn't look the same now. 1
DXB Posted June 20, 2016 Report Posted June 20, 2016 50 minutes ago, N1395W said: On my 64C (as well as my previous 67C) the SCAT tube extends aft to blow air on the mechanical fuel pump. It gets secured wherever you can to generally direct air to the back of the engine. Huh - learned something here. I guess it goes to a cooling shroud around the engine driven pump, designed to prevent vapor lock in the pump on hot days. Mine is missing the hose and shroud entirely - just has the hole in the front of the cowl. How important is this- should I care? Or should I plug the hole in the cowl?
Andy95W Posted June 20, 2016 Report Posted June 20, 2016 (edited) Neither one of my C's had a shroud around the engine driven fuel pump, just the SCAT tubing pointed generally in its direction. If you don't have anything connected to yours, I would block it off just like you said. Maybe cut a circular piece of strong black tape to stick on the hole from the outside. Then, at your next annual, consider adding the scat tubing. Edit- I honestly don't know how important it is, since yours doesn't have it and you don't have any problems. Maybe it has an effect on really hot days, or in southern Alabama where Hank lives? Edited June 20, 2016 by N1395W
carusoam Posted June 20, 2016 Report Posted June 20, 2016 Is it possible that cooling the FP came after '65? the mismatch in size from the ram air entrance to the generator's hose was a pseudo conic shape. Mine was not a precision piece when I owned it... added thoughts... 1) alternators get their own cooling fans to drive air to the proper place. 2) keeping fuel cool can prevent vapor bubbles from forming. 3) if the fuel pump is cooled differently in later years, it may make an interesting improvement. 4) consult with your mechanic for this level of work. It would be important to get it right. PP ideas only, I am not a mechanic. Best regards, -a-
Guest Posted June 20, 2016 Report Posted June 20, 2016 8 hours ago, N1395W said: On my 64C (as well as my previous 67C) the SCAT tube extends aft to blow air on the mechanical fuel pump. It gets secured wherever you can to generally direct air to the back of the engine. Attached is a picture of mine. The tube in question is the one that appears to be laying on the oil cooler and runs back to where it disappears behind the #4 intake riser. As I said, it points to the mechanical fuel pump. P.S. Please feel free to comment on anything else you see in the photo that is wrong (especially M20Doc- Clarence). I took this picture when I was doing the first annual on my (new to me) M20C. It doesn't look the same now. As with Bonal's plane, yours seems to be missing 4 cylinders. Perhaps Mooney forgot them. Clarence
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